<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="vue2.2.js"></script>
</head>
<body>
<div id="app">
    <child content="He">

    </child>
</div>
<script>
    Vue.component('child', {
        props: {
            content: {
                validator: function (value) {
                    return (value.length > 5)
                }
            }
        },
        template: '<h1>{{content}}</h1>'
    });
    var vm = new Vue({
        el: '#app'
    })
</script>

</body>
</html>